1. Field of the Invention
The present invention relates to magneto-optical recording media, particularly to the structure of a magneto-optical recording medium including predetermined periodic discontinuous regions at the land or groove.
2. Description of the Background Art
Attention is focused on the magneto-optical recording medium as a rewritable and reliable recording medium of large storage capacity. The magneto-optical recording medium has began to be actually used as the computer memory and the like. Recently, the standard of AS-MO (Advanced Storaged Magnetic Optical) is in progress as a magneto-optical recording medium having the storage capacity of 6.0 Gbytes for practical usage. As shown in FIG. 1, the magneto-optical recording medium of such a high density has a plane structure in which a groove 40 and land 41 having the width of approximately 0.6 .mu.m are formed alternately in the radial direction. Discontinuous regions are provided periodically at groove 40 and land 41. More specifically, landed regions 42 are periodically formed at groove 40. Also grooved regions 43 are formed periodically at land 41.
In recording and/or reproducing a signal onto or from the magneto-optical recording medium, discontinuous regions 42 and 43 provided at groove 40 and land 41 are detected to generate a periodic fine clock signal from which a synchronizing signal is generated.
In the magneto-optical recording medium having a plane structure as shown in FIG. 1, further reduction of the width of groove 40 and land 41 for a higher density than the storage capacity of 6.0 Gbytes will result in a lower signal intensity for the detection of discontinuous regions 42 and 43 as shown in FIG. 2. The discontinuous regions 42 and 43 cannot be detected properly. Thus, there is a problem that is difficult to generate an accurate synchronizing signal.